Method Detail

addChangeHandler

Called when a FormItem's value is about to change as the result of user interaction. This method fires after the user
performed an action that would change the value of this field, but before the element itself is changed.

Returning
false cancels the change. Note that if what you want to do is transform the user's input, for example,
automatically change separator characters to a standard separator character, you should implement transformInput rather than using a combination of
change() and setValue() to accomplish the same thing. Returning false from change is intended for
rejecting input entirely, such as typing invalid characters.

Note that if you ask the form for the current value in
this handler, you will get the old value because the change has not yet been committed. The new value is available as a
parameter to this method.